Longwall cutter and reciprocating weight therefor



w. w. sLoANE 2,690,903

LONGWALL CUTTER AND RECTPROCATTNG WEIGHT THERETOR Oct. 5, i954 5sheets-sheet 1 Filed Ooi. 17, 1952 MAZ INVENTOR.

WILLIAM W, SLOANE v BY rme/vry 5 Sheets-Sheet 2 Oct. 5, 954 w. w. sLoANELONGWALL CUTTER AND RECIPROCATING WEIGHT THEREFOR med oct. 17. 1952 W.W. SLOANE Ust. 5, 1954 LONGWALI.. CUTTER AND RECIPROCATING WEIGHTTHEREFOR Filed Oct. 17, 1952 5 Sheets-Sheet 3 INVENTOR.

WILLIAM W. SLOANE y .74 TraRNEy LONGWALL CUTTER AND RECIPROCATING WEIGHTTHEREFOR Filed Oct. 17, 1952 5 Sheets--Shee'l'I 4 37 INVENTOR.

WILLIAM W. SLOANE w. w. sLoANE 2,690,903

LONGWALL CUTTER AND RECIPROCATING WEIGHT THEREFOR Oct. 5, i954 5Sheets-Sheet 5 Filed 0G12. 17, 1952 INVENTOR.

WHL-mm W, SLOANE BY Patented Oct. 5, 1954 UITED STATES OFFICE LONGWALLCUTTER AND RECIPROCATING WEIGHT THEREFOR Application October 17, 1952,Serial No. 315,337

Claims.

The invention relates generally to machines for mining coal or the likeand relates particularly to a continuous mining machine for use in thelongwall method of mining.

Previous machines for continuously mining coal by the longwall methodhave entailed the use of scoops or buckets mounted on supports or frameswhich are moved along the working face by draft means which with thescoops operate to plow or plane the coal from the seam. In such machinesthe draft means are subjected to loads ranging from 6,000 pounds to40,000 pounds depending upon the hardness of the coal and the depth ofcut, and no provision has heretofore been made whereby the scoop orbucket is additionally implemented by impact forces when the steady loadon the draft means is insufficlentto remove the coal.

In carrying out the present invention a pick or cutter is maintained incontact with the face by draft means connected to a frame supporting thepick. impulses against the coal are provided by the cutter and areciprocating weight having desired velocity and accelerationcharacteristics, the weight being connected to the cutter by a linkageand being so arranged that the changing momentum of the weight istransmitted by the linkage into the cutter in the form of an impulse ofshort duration.

The impulses transmitted into the cutter create conditions of localizedstress in the coal so that it is planed or plowed from the seam and onto a flight conveyor. Such impulses are of extremely short duration, andgreatly exceed the crowding force against the cutter caused by the draftmeans, but at all times the crowding force is kept to a constantminimum. During times when the cutter encounters resistance, thereciprocating weight will provide continued impulses through the mediumof the linkage until the coal is weakened by such continued impulses andis planed from the seam, the draft means maintaining the cutter againstthe seam at all times while it is encountering resistance.

The machine according to the present invention is also characterized bybeing able to operate readily in either direction along the face of theseam, the cutter having cutting edges at each end thereof, and beingcapable of exerting a combined shearing and punching force in eitherdirection. Operation in the opposite direction is achieved by a pair ofselective gear trains chosen to give desired angular velocities to acrank and connecting rod connected to the reciprocating weight, one suchgear train being operable for one direction of working movement of thecutter, the other gear train being operable for the other direction ofworking movement of the cutter.

With the foregoing considerations in mind it is a principal object ofthe invention to alford an improved machine for the continuous mining ofcoal by the longwall method, and to exert a combined punching andshearing action against the coal of such seam, and to employ thepunching forces to minimize the crowding force exerted by the draftmeans.

Other objects and important features of the invention will be apparentfrom a study of the following specification taken with the drawingswhich together illustrate a preferred embodiment of the invention andwhat is now considered to be the best mode of applying the principlesthereof. Other embodiments of the invention may be suggested to thosehaving the benefits of the teachings herein and it is therefore intendedthat the invention not be limited by the precise embodiment shown, norotherwise than by the scope and purview of the subjoined claims.

In the drawings:

Fig. l is a general top plan View of the improved continuous miningmachine according to the present invention;

Fig. 2 is a general front elevation View thereof;

Fig. 3 is a detailed plan view to a larger scale of the machine of Fig.1, showing details of the operating mechanism thereof;

Fig. 4 is an elevation view taken inside the front wall of the machine,said view being taken substantially along the line -fi of Fig. 3;

Fig. 5 is a transverse section taken substantially along the line 5-5 ofFig. 4 looking in the direction of the arrows; and

Fig. 6 is a perspective view of a snubbing device for checking themovement of the reciprocating weight when the pick is no longerencountering resistance.

General description of machine Referring now particularly to Figs. l and2 of the drawings the improved machine according to the presentinvention is referred to generally by the reference numeral l0, andincludes a main vertical frame il which forms part of an enclosure for areciprocating weight l2 arranged to impart an impulse into a cutter orpick I3, so that the points lll or lila. thereof will bear against anexposed bench IS of a coal seam il to shear or plane the coal from theseam Il. The machine l0 is particularly adapted to the long wall systemof mining instead of the usual room and pillar method of mining and isso arranged as to traverse the length of the seam I'E while the cuttertip I4 or Illa'r of the pick I3 is planing the coal therefrom.

The main frame I I forms a support for a housing indicated generally bythe reference numeral I8, see also Fig. -3, the housing I8 including afront wall I9, a top cover 2l and a lower base plate 22. The top cover2I and the base plate 22 are secured to the front Wall I9 as byweldments 23, 24, and the top plate 2I and the lower base plate 22 areprovided with flanges 29 and 2l whereby the housing I8 may be held tothe main frame Il as by cap screws 28.

Referring back again to Figs. l and 2 of the drawings, the frame II isprovided at each end thereof with deecting vanes 29, 29, the lower edgesof which rest upon the mine oor. The vanes 29 are spaced a distance backfrom the cutter tips i4 and I4a, and are arranged to flare back upon adouble strand flight conveyor indicated generally by the referencenumeral 3I, so that as the coal is sheared from the face I'I by thecutter tip Hl or Ida it will be directed on to the flight conveyor.

The flight conveyor 3| includes side channel sections 32 which arespanned by a web number forming a support for the upper reach offlights, the lower or return reach having its ends resting upon thelower flanges 34 of the channel members 32. The channel members aresupported at intervals throughout their length upon shoes 35 restingupon the mine oor.

The channel member 32 positioned closest to the seam I'I is provided atintervals throughout its length with a bracket 31 for a tubular supportrail 38 for the mining machine I0. As best seen in Fig. 5, the lowerpart of the deflecting vane 29 is provided with a se1ni-cylindricalflange 39 resting upon the tubular rail 38, the deilecting vanes and theframe I I being prevented from riding up out of engagement with thetubular rail by a ange member @I bolted to the deflecting vane by bolts32. It will be seen that the flange members 38 and 1li embrace more than180 of central angle of the tubular rail 38 so as to hold the deflectingvanes 29 and the frame II to the rail 33 at all times.

The machine I9 is arranged to be moved along the face I'I by draftchains i3 which are connected to suitable Winches or hoists, not shown,disposed beyond the ends of the seam Il. As seen in Fig, 3, the returnrun of the chain d3 is guided within the tubular rail 38, so that themachine traverses the face Il in either direction the return run of thechain will be suitably protected against being run over by the machine.It may be noted that the hoists or winches disposed at each end of theseam I'I are so arranged that one is inoperative while the other ispulling the machine across the face Il.

Description of impulse transmitting mechanism for cutters Referringparticularly to Figs. 3 and 4 of the drawings, reciprocating movement isgiven to the weight I2 by means of a motor 44 supported in anyconvenient fashion on the forward wall I9 of the housing I9. The motori4 is connected through a fluid coupling and flywheel 46 to turn a studshaft il? mounted in a bearing support 48 secured to the wall I9 of thehousing I8. A miter gear i9 is made fast to the end of the stub shaft4l, and meshes with a miter gear 5I fast upon a lay shaft 52 supportedin bearings 53 and 54. Standards 5B, 51 are provided to mount thebearings 53 and 5Ll, and are secured to the front wall I9 in anyconvenientl fashion.

The lay shaft 52 is provided with a pair o1 eccentrically mountedpinions 58 and 59 which are selectively connected to be driven by thelay shaft 52 by means of a splined clutch GI splined to the lay shaft52. The spline clutch SI is shifted to a position of engagement witheither gear 58 or 59 by means of a shift lever 62 made fast to a rockshaft 63 turning within a boss 64 on the inside of the front wall I9, asseen more particularly in Fig. 5. A handle 69 is made fast to the rockshaft 63 so that the lever 92 can shift the spline clutch 6I to positionof clutching engagement with either pinion 58 or 59.

A crank shaft B'I, see particularly Fig. 4, is supported on bearings E8,G9 and II which are respectively mounted in bearing standards l2, 73 andlll, said bearing standards being secured in any convenient fashion towall I 9 of the housing I8, see particularly Fig. 5. The crank shaft 67has fast thereon a pair of variable speed gears '.'6 and 'VI of the typeas disclosed in Sloane Patent No, 2,585,971, issued February 19, 1952,for Gearing. Said gears are designed to give desired angular velocity tothe crank shaft Gi when meshing with eccentrically mounted pinions 58 or59 mounted upon the lay shaft A flywheel 65 is mounted on the shaft 6?to give desired rotational inertia to the shaft, so that loadstransmitted by the motor il and crank shaft S'I will not appreeiablyaffect the speed thereof.

Each end of the crank shaft E? is fitted with a crank It having a crankthrow l9. A connecting rod 8l is mounted on the throw i9 and is providedwith a clevis 82 at one end thereof. A bell crank 83 is connected by apin t/i to the connecting rod 8| at the clevis 92, and is pivoted at 86to the reciprocating weight I2, the link being held pivotally to theweight by a cap bolt 8'! tapped into the weight I2. The opposite end ofthe bell crank 83 terminates in a clevis Bil which forms a point ofconnection to a drag link 99 hingedly connected at 9i to a bracket 92mounted along the top of the pick I3 as seen in Fig. Zl.

It will be noted from Fig. 4 that the assembly for linking the crankshaft to both the reciprocating weight i2 and the cutter Id are disposedon both the top and bottom edges of the cutter I4 and the weight I2. Thedescription obtaining for one such assembly, which assembly has beendescribed in connection with the upper assembly, is believed to suiicefor the lower of such assemblies.

The cutter I3 is guided in its position alongside the frame I I, andbetween the frame I l and the face of the seam I'I by means of a slot G3disposed in the top and the bottom of the cutter I3, and a block 94arranged to be held on a pin 96 held in an angle member 9i bolted at 9Gto the outside of the frame I I.

The weight I2 is guided in its reciprocating movement by guide blocks 99which ride in a groove IGI formed in both the top and the bottom of thereciprocating weight I2. rI'he guide blocks 99 are inserted throughapertures 292 in the top cover 2l and the bottom plate 22 and are heldin position by cap screws I G3.

The variable speed gear 'VI and the crank i3 are arranged to transmitthrough the connecting rod 8l a desired motion to the bell crank 83,which when the cutter I4 is in contact with the bench I6, will in turntransmit a linear motion to the reciprocating weight I2. The linearmotion of the weight I2 is so chosen that upon a change in momentumthereof an impulse will be transmitted by the bell crank 83 into thecutter I so as to cause the coal to be sheared or planed from the seamI'I. The precise details of the motion of the Weight I2 to give thedesired impulse against the bit Isl is discussed in more detail in theco-pending application of William W. Sloane, Serial No. 293,958 filedJune 17, 1952, for Mechanical Miner.

In the other direction of movement when the cutter tip E 4a is inengagement with the seam I'l, the gear 'it is drivably connected withthe eccentric pinion 52 so that the proper velocity is imparted to theweight I2 for creating impulses against the cutter Ilia.

Description of crowd for cutting Means are provided so that the crowdingaction of the draft chain 43 is maintained against the cutter i4, and insuch a fashion that while the crowding force is maintained against theseam il, the cutter may move together with the weight i2 with respect tothe draft means 43 effecting crowding movement. To this end the cutterarm i3 is provided with a V-shaped cam |04, the throat of the V being ina direction toward the housing i3. rThe cam Ii cooperates with a camfollower arm IIii having a cam roller I? at the end thereof. The camroller IIlI rides upon the V-cam surface |32, and the movement of theroller itil in a direction as would be occasioned by the movement of thecutter arm I3 either in a forward direction to the right as seen in Fig.3, or in a rearward direction, is opposed by a piston rod |33 connectedto a piston, not shown, slidable in a cylinder I 33. The cylinder |09 issecured to the housing of the motor 44 in any convenient fashion as seenmore clearly in Figs. 3 and 4.

The movement of the cutter |3, as would occasion the riding of the camroller |07 upon either of the V-cam surfaces |34, would normally tend tocause the arm I3 to rock about the pin 96. However, the reciprocatingWeight l2, see particularly Figs. 4 and 5, is provided with stabilizingrollers mounted on brackets I|2 secured to the side of the weight i2where it is nearest to the frame I I. As seen in Fig. 4, the frame |I isprovided with openings |I3, so that as the weight I2 reciprocates withrespect to the fra-me II, the rollers I|| may freely move in the slots ii3 whilst bearing against the inside of the cutter arm I3.

Description of mechanism for arresting Znngz'ng movement of thereciprocating weight The reciprocating Weight I2 has been described asimparting an impulse upon changes in momentum thereof into the cutterarm I3 linked thereto. Under certain conditions when resistance is nolonger afforded by the bench I6, the inertia of the reciprocating weightI2 will cause it to lunge in a direction parallel to and toward thecutter tip Il! of the cutter arm I 3. In order to prevent such lungingmovement of the reciprocating weight I2, it is restrained partly in suchmovement until it again resumes a motion which is consistent with or isa function of its mass as compared with the mass of the cutter arm I3.

As seen more particularly in Figs. 4 and 6, the weight I2 is provided atthe forward end thereof with a lug H2 which engages abutments ||5 or|I5a disposed on a stop arm I|6 pivotally connected to a pair of rockarms II'I hingedly connected at I|8 to an abutment IIS extending upwardfrom the bottom plate point 22. The stop arm I I6 is connected to a pinshaft |2| of a combined brake applying and'return arm |22 which ishingedly connected at |23 to a fixed abutment |24 also extending upwardfrom the bottom plate 22. The pin shaft |2| provides a support for aplurality of brake shoes |26 spaced thereon, each brake shoe |26 beingspaced by blocks of frictional material |27 which are anchored at theirends remote from the rock arms |II on pins |32 passing through anglemembers I3| extending from an abutment plate |29, said abutment platedepends from the underside of a support plate |28 extending inward fromthe wall I9 and secured thereto in any convenient fashion.

The amount of pressure between the brake shoes |26 and the blocks offriction material I2`| is adjusted by a brake adjusting arm |33 which ispivoted at |34 substantially centrally thereof to a pressure plate |35which bears against the outermost brake shoe |26'. One end of theadjusting arm |33 bears against a spring |37 bearing against the insideof the wall I 9, the amount of pressure between the brake shoes |25 andthe lining material |2'I being adjusted by a set screw |38 bearingagainst the other end of the arm |33 and threaded into the front wallI9.

The pressure plate |36 is preferably formed integrally with an arm, notshown, which extends beneath the brake shoes |26 and the friction blocks|21 for support thereof.

It will be seen that when the weight I2 lunges in a forward direction,that is, in a direction toward the right as seen in Figs. 3 and 4, thelug |4 will engage the abutment I I5 on the arm I I3 which in turn willrock the brake applying arm |22 in a clockwise direction as seen in Fig.6, causing a braking action between the brake shoes |26 and the liningmaterial |21, thereby arresting the lunging movement of the weight I2.

The brake applying and the return arm I 22 has connected thereto apiston rod |33 which is slidable with a piston, not shown, within afloating cylinder MI which moves between spaced abutments |52 and |43 onthe support plate |23, being guided between the spaced abutments I 42and |43 by spaced rails |44 and |46. Prior to the action previouslydescribed, that is when the weight I2 lunges to the right as seen inFig. 4, the piston rod end of the cylinder IM is in engagement with theabutment |43, air being trapped at super-atmospheric pressure betweenthe piston thereof and the piston rod end of the cylinder |4I.

The lunging movement of the weight I2 will cause the brake applying arms|22 to rock in a clockwise direction as previously described, at thesame time moving the piston within the cylinder |4I towards the pistonrod end thereof. The force against the piston within the cylinder |41 issufricient to overcome the friction between the brake shoes |26 and thebrake lining |21 so that the arm I2 2 may be rocked slowly in acounter-clockwise direction causing the arm ||6 to return to its normalposition, that is when the piston within the cylinder |4| has moved tothe cylinder head end thereof.

Meanwhile the'we'ight |2 will have commenced once more to have resumedits normal reciprocating movement, and the brake applying arm IIS andthe floating abutment |5 will be in position once more to arrest thelunging movement of the weight I2 at times when the pick |3 is no longerencountering resistance from the bench I6.

Under conditions when the machine ID is operated in .a direction fromthe rightto the left, the lack of resistance afforded by the seam I'Iwill cause the weight I2 to lunge to the left as seen in Fig. 6. Undersuch condition of operations the cylinder Ill! is charged with air atsuper-atmospheric pressure between the piston and the cylinder head endthereof until the cylinder It! is in engagement with the abutment M2. Itis obvious, of course, that suitable means may be provided to charge thecylinder Ill! at either the cylinder` head end or the piston rod endthereof.

Under such latter conditions of operation of the machine I0, and attimes when the weight I lunges to the left, as has been described, thelug I I4 will engage the floating abutment I Ida on the brake applyingarm IIS causing a similar operation of the brake as previouslydescribed, but in an opposite direction. However, the air trappedbetween the cylinder head and the piston of the cylinder IBI will causethe arm I22 to be rocked in a clockwise direction as seen in Fig. 6until the assembly is returned to its normal position with the piston ofthe cylinder IllI bearing against the piston rod end thereof.

Operation In the operation of the mining machine according to thepresent invention it is advanced by the crowd chain i3 against alongwall face as seen in Fig. l. The impulse transmitting mechanismlocated within the space defined by the frame II and the housing I8 isdriven from the motor 41%. The crowding effect of the draft chain i3 maybe of the order of 8,000 pounds, but when reciprocating movement isgiven to the weight I2 by the motor MI, and the gear train and linkagepreviously described, there will be at times an instantaneous impulsetransmitted against the cutter I4 of the order of 25,000 pounds.

Prior to the contact by the cutter ifi with the seam I 'I the cutterwill have a reciprocating motion with a longer stroke as compared to thestroke of the weight I2, the difference in magnitude of such strokesbeing in accordance with the ratio of the mass of the reciprocatingweight I2 to the mass of the cutter arm I3. When the cutter Ill comesinto contact with the coal seam its stroke decreases but the stroke ofthe weight I2 increases until the resistance of the coal becomes equalto the low accelerating force of the weight I2. As long as theresistance of the coal exceeds the force of the low acceleration of theweight I2, the cutter I4 will continue to Contact the coal seam I'I. Infragmenting the coal against any higher resistance the advance of thecutter will be intermittent while the feed movement by the draft chainwill be reasonably constant. The bell crank 83 affording the connectionbetween the weight IQ and the cutter ill enables intermittent advancingof the cutter head I4 while the crowd from the draft chain i3 will bemaintained substantially uniform. While such crowd is maintained at theuniform rate and the cutter fails to move in accordance with such crowdmovement the cam follower IBG will move along the V-cam surface Iill.

At the beginning of a cutting cycle the weight i2 is accelerated towardthe cutter ill but the reacting force from this acceleration is opposedby the crowding force from the draft chain 43. As long as the crowdingdue to the draft chain $3 is greater than the reacting force induced bythe weight I2 in its low acceleration rate toward the cutter I4, thecutter will be held in contact with the coal with a force which isequalto the difference between the crowding force reacting force. Nearthe end of the stroke of the weight I2 its motion is changed to one ofrapid deceleration, and the force of the deceleration plus the crowdforce are applied together to the cutter Ill. This combined force ismaintained during the rapid backward acceleration of the weight I2 andduring this period such force is maintained the cutter I4 will advanceinto the bench I 6 with increasing velocity. When the velocity of thecutter Ill attains a value which is in excess of that caused by thecrowd of the draft chain alone the V-cam IIN will enable the cutter I3to advance with respect to any advance which would normally be achievedby the crowd alone.

At the point where rapid backward acceleration of the weight I2 ceaseswith respect to the cutter I3 the cutter may be moving forward withconsiderable velocity. The weight I2 has a dennite relative motion withrespect to the cutter i4 which would enable the weight to be movingbackward relative to the cutter I3, but since the cutter may have aforward velocity which may be higher than the maximum relative velocityof the weight I2, the absolute motion of the weight I 2 may be still ina forward direction. At this point the motion of the weight changes toone of slow reverse deceleration with forces which are in a direction toretard the weight I2, but the absolute forward momentum of the weight I2and the cutter I3 will cause the cutter to continue to advance with adecreasin'Jr velocity until its motion ceases, where it remains incontact with the face of the seam until the high forces are appliedduring the succeeding cycle of the weight and the cutter.

The highest force which can be applied by the cutter I3 is when thecutter is stalled against material which it cannot penetrate. Obviously,if the resistance of the material is less than the stalling forceagainst the cutter the coal will be fragmented from the seam and thecutter will be accelerated in a forward direction, the high forces ofdeceleration and backward acceleration of the weight I2 being reduced bysuch force of acceleration of the cutter in a forward direction.

The V-cam I0@ also provides a means for correcting the tendency of thecutter to accelerate when resistance is no longer afforded by the coalseam. Without the V-cam surface the cutter would normally lunge forward,but the resistance to the movement of the piston rod I0I of the cylinderE00 prevents such lunging movement, any lunging movement permittedcausing the roller I0? to ride on one of the V-cam surfaces.

Under conditions when it is desired to operate the miner from the rightto the left as seen in the several gures, the operating handle 0G asseen in Fig. 5 is rocked to a position whereby the ,spline clutch 0Icauses the eccentric pinion 58 to be made fast to the shaft 52 therebyaffording driving connection to the variable speed gear '55. It will benoticed that the eccentric driving pinions E and 52 are disposed 180apart as are the varying speed gears '6 and il, so that the .sequence ofoperations obtaining as previously described will be carried on, but inthe reverse direction, the cutter tip Illa then engaging the .team toshear or plane the coal therefrom.

In either direction of operation the draft means 43 will move themachine I0 along the tubular rail 38 as seen in Fig. 5, one of theWinches or hoisting means being inoperable acand the forward 9 cordingto the direction of the machine along the rail 38.

It may be noticed that the double strand night conveyor 3l is advancedtogether with the machine lil as the coal is completely fragmented fromthe seam after a complete pass thereof along the face. Jacks, not shown,or suitable hydraulic means may be interposed between the outer channel32 and a fixed abutment, so that when a pass is completed the conveyor3| together with the machine l may be moved to another position for asubsequent pass in an opposite direction along the face Il.

The mechanical miner according to the present invention presents manyadvantages, one being that relatively large fragments of coal are cutfrom the seam by its use. The machine according to its present inventionis also capable of use without the necessity of extremely large crowdingforces for moving the machine and its cutter along the face, such as hasbeen necessary with machines of the prior art where the coal is shearedor planed from the seam by brute force. Since the coal is not subjectedto the tearing action of cutter bits such as are used in conventionalcontinuous miners, the presence of dust at the working face is minimizedto a great eX- tent. The provision of the deflecter vanes at each end ofthe machine enables the coal fragmented from the seam to fall readilyupon the flight conveyor 3! to be transmitted from the working face witha minimum of handling.

Since the machine according to the present invention is particularlyadapted for the long wall method of mining, the total amount of coalcapable of being removed in a mining operation is much greater than ispossible by the conventional room and pillar method.

While the invention has been described in terms of a preferredembodiment thereof its scope is not intended to be limited by theprecise embodiment herein shown nor otherwise than by the terms of theclaims here appended.

l claim:

1. In a mechanical miner particularly adapted to move with respect to alongwall face of a seam of frangible material, a frame having draftmeans located at each end of said longwall and connected to said framefor moving said frame with respect to said face, a conveyor disposedalongside said frame and forming a means for supporting said frame formovement therealong, a cutter arm arranged to move with said frame andwith respect to said frame and having a cutter at each end thereof forcontacting said face according to the direction of movement of saidframe so as to plane or plow material from said seam, a reciprocatingweight supported by said frame and arranged to reciprocate with respectto said cutter, a motor for imparting reciprocating movement to saidWeight with respect to said cutter, said motor providing foracceleration of said weight during the major portion of its travel whensaid weight is moving in a direction towards said cutter, a linkageconnecting said weight and said cutter for transmitting an impulse intosaid cutter from said weight in response to changes in momentum of thelatter, means selectively driven from said motor so as to providedesired reciprocating movement to said weight according to the directionof said frame along said conveyor, and means for arresting said weightin its travel toward said cutter when said cutter is no longerencountering resistance from said seam, said last named means beingoperable irrespective of the direction of movement of said frame alongsaid conveyor.

2. In a mechanical miner particularly adapted to move with respect to alongwall face of a seam of frangible material, a frame having draftmeans located at each end of said longwall and connected to said framefor moving said frame with respect to said face, a conveyor disposedalongside said frame and forming a means for supporting said frame formovement therealong, a cutter arm arranged to move with said frame andwith respect to said frame and having a cutter at each end thereof forcontacting said face according to the direction of movement of saidframe so as to plane or plow material from said seam, a reciprocatingweight supported by said frame and arranged to reciprocate with respectto said cutter, a motor for imparting reciprocating movement -to saidweight with respect to said cutter, said motor providing foracceleration of said weight during the major portion of its travel whensaid weight is moving in a direction towards a cutter in contact withsaid face, a linkage connecting said Weight and said cutter fortransmitting an impulse into said cutter from said weight in response tochanges in momentum of the latter, and means selectively driven fromsaid motor so as to provide desired reciprocating movement to saidweight according to the direction of said frame along said conveyor.

3. In a mechanical miner particularly adapted to move with respect to alongwall face of a seam of frangible material, a frame having draftmeans located at each end of said longwall and connected to said framefor moving said frame with respect to said face, a cutter arm arrangedto move with said frame and with respect to said frame and having acutter at each end thereof contacting said face according to thedirection of movement of said frame so as to plane or plow material fromsaid seam, a reciprocating weight supported by said frame and arrangedto reciprocate with respect to said cutter, a motor for impartingreciprocating movement to said weight with respect to said cutter, saidmotor providing for acceleration of said weight during the major portionof its travel whensaid weight is moving in a direction towards saidcutter, a linkage connecting said weight and said cutter fortransmitting an impulse into said cutter from said weight in response tochanges in momentum ofthe latter, means selectively driven from saidmotor so as to provide desired reciprocating movement to said weightaccording to the direction of movement of said frame along said seam,and means for arresting said weight in its travel toward said cutterwhen said cutter is no longer encountering resistance from said seam,said last named means being operable irrespective of the direction ofmovement of said frame along said seam.

4. In a mechanical miner particularly adapted to move with respect to alongwall face of a seam of frangible material, a frame having draftmeans located at each end of said longwall and connected to said framefor moving said frame with respect to said face, a cutter arm arrangedto move with saidvframe and with respect to said frame and having acutter at each end thereof contacting said face according to thedirection of movement of said frame so as to plane or plow material fromsaid seam, a reciprocating weight supported by said frame and arrangedto reciprocate with respect to said cutter, a motor for impartingreciprocating movement to said weight with respect to said cutter, saidmotor providing for acceleration of said weight during the major portionof its travel when said weight is moving in a direction towards saidcutter, a linkage connecting said weight and said cutter fortransmitting an impulse into said cutter from said weight in response tochanges in momentum of the latter, and means selectively driven fromsaid motor so as to provide desired reciprocating movement to saidweight according to the direction of movement of said frame along saidseam.

5. In a mechanical miner particularly adapted to move with respect to alongwall face of a seam of frangible material, a frame having draftmeans located at each end of said longwall and connected to said framefor moving said frame with respect to said face, a cutter arm arrangedto move with said frame and with respect to said frame and having acutter at each end thereof for contacting said face according to thedirection of movement of said frame so as to plane or plow material fromsaid seam, a reciprocat- 25 ing weight supported by said frame andarranged to reciprocate with respect to said cutter arm, a motor forimparting reciprocating movement to said weight with respect to saidcutter arm, said motor providing for acceleration of said weight duringthe major portion of its travel when said weight is moving in adirection towards said cutter, and a linkage connecting said weight andsaid cutter for transmitting an impulse into said cutter from saidweight in response to changes in momentum of the latter, and gear meansinterposed between said motor and said reciprocating weight forselectively reciprocating said weight with desired velocity andacceleration characteristics according to the direction of movement ofsaid frame.

References Cited in the le of this patent UNITED STATES PATENTS NumberName Date 2,565,528 Sloane Aug. 28, 1951 2,610,841 Pearson et al Sept.16, 1952 FOREIGN PATENTS Number Country Date 647,491 Great Britain Dec.13, 1950

